2,319 research outputs found
Congestion games with load-dependent failures: identical resources
No full textWe define a new class of games---congestion games with load-dependent failures (CGLFs). In a CGLF each player can choose a subset of a set of available resources in order to try and perform his task. We assume that the resources are identical but that players' benefits from successful completion of their tasks may differ. Each resource is associated with a cost of use and failure probability which are load-dependent. Although CGLFs in general do not have a pure strategy Nash equilibrium, we prove the existence of a pure strategy Nash equilibrium in every CGLF with nondecreasing cost functions. Moreover, we present a polynomial time algorithm for computing such an equilibrium
Random order congestion games
No full textWe introduce a new class of games, Random Order Congestion Games [ROCGs]. In an ROCG, each player has a task that can be carried out by any element of a set of resources, and each resource executes its assigned tasks in a random order. Each player's aim is to minimize his expected cost which is the sum of two terms---the sum of the fixed costs over the set of his utilized resources and the expected cost of his task execution. The cost of a player's task execution is determined by the earliest time his task is completed, and thus it might be beneficial for him to assign his task to several resources. We prove the existence of pure strategy Nash equilibria in ROCGs. Moreover, we present a polynomial time algorithm for finding such an equilibrium in a given ROCG
Taxed Congestion Games with Failures
No full textIn this paper, we introduce and study Taxed Congestion Games with Failures [TCGFs], extending congestion games with failures [CGFs] to consider costly task submission. We define TCGFs, and prove that TCGFs possess a pure strategy equilibrium. Moreover, we provide an efficient algorithm for the computation of such equilibrium. We also provide a specialized, simpler, algorithm for the case in which all resources are identical
Congestion Games with Failures
No full textWe introduce a new class of games, {\it congestion games with failures} (CGFs), which allows for resource failures in congestion games. In a CGF, players share a common set of resources (service providers), where each service provider (SP) may fail with some known probability (that may be constant or depend on the congestion on the resource). For reliability reasons, a player may choose a subset of the SPs in order to try and perform his task. The cost of a player for utilizing any SP is a function of the total number of players using this SP. A main feature of this setting is that the cost for a player for successful completion of his task is the \underline{minimum} of the costs of his successful attempts. We show that although CGFs do not, in general, admit a (generalized ordinal) potential function and the finite improvement property (and thus are not isomorphic to congestion games), they always possess a pure strategy Nash equilibrium. Moreover, every best reply dynamics converges to an equilibrium in any given CGF, and the SPs' congestion experienced in different equilibria is (almost) unique. Furthermore, we provide an efficient procedure for computing a pure strateguy equilibrium in CGFs and show that every best equilibrium (one minimizing the sum of the players' disutilities) is semi-strong. Finally, for the subclass of symmetric CGFs we give a constructive characterization of best and worst equilibria
Asynchronous Congestion Games
No full textWe introduce a new class of games---asynchronous congestion games (ACGs). In an ACG, each player has a task that can be carried out by any element of a set of resources, and each resource executes its assigned tasks in a random order. Each player's aim is to minimize his expected cost which is the sum of two terms---the sum of the fixed costs over the set of his utilized resources and the expected cost of his task execution. The cost of a player's task execution is determined by the earliest time his task is completed, and thus it might be beneficial for him to assign his task to several resources. We prove the existence of pure strategy Nash equilibria in ACGs. Moreover, we present a polynomial time algorithm for finding such an equilibrium in a given ACG
Congestion Games with Load-Dependent Failures: Identical Resources
No full textWe define a new class of games---congestion games with load-dependent failures} (CGLFs), which generalizes the well-known class of congestion games, by incorporating the issue of resource failures into congestion games. In a CGLF, agents share a common set of resources, where each resource has a cost and a probability of failure. Each agent chooses a subset of the resources for the execution of his task, in order to maximize his own utility. The utility of an agent is the difference between his benefit from successful task completion and the sum of the costs over the resources he uses. CGLFs possess two novel features. It is the first model to incorporate failures into congestion settings, which results in a strict generalization of congestion games. In addition, it is the first model to consider load-dependent failures in such framework, where the failure probability of each resource depends on the number of agents selecting this resource. Although, as we show, CGLFs do not admit a potential function, and in general do not have a pure strategy Nash equilibrium, our main theorem proves the existence of a pure strategy Nash equilibrium in every CGLF with identical resources and nondecreasing cost functions
Considerate Equilibrium
No full textWe study the existence and computational complexity of coalitional stability concepts based on social networks. Our concepts represent a natural and rich combinatorial generalization of a recent notion termed partition equilibrium {Feldman09}. We assume that players in a strategic game are embedded in a social (or, communication) network, and there are coordination constraints defining the set of coalitions that can jointly deviate in the game. A main feature of our approach is that players act in a "considerate' fashion to ignore potentially profitable (group) deviations if the change in their strategy may cause a decrease of utility to their neighbors in the network. We explore the properties of such considerate equilibria in application to the celebrated class of resource selection games (RSGs). Our main result proves existence of a super-strong considerate equilibrium in all symmetric RSGs with strictly increasing delays, for any social network among the players and feasible coalitions represented by the set of cliques. The existence proof is constructive and yields an efficient algorithm. In fact, the computed considerate equilibrium is a Nash equilibrium for a standard RSG, thus showing that there exists a state that is stable against selfish and considerate behavior simultaneously. Furthermore, we provide results on convergence of considerate dynamics
Weekly assessment of worry: an adaptation of the Penn State Worry Questionnaire for monitoring changes during treatment
No full textAn adaptation of the Penn State Worry Questionnaire (PSWQ) [Meyer, T. J., Miller, M. L., Metzger, R. L. and Borkovec, T. D. (1990). Development and validation of the Penn State Worry Questionnaire. Behaviour Research and Therapy, 28, 487-495.] for weekly assessment of worry was evaluated in a brief treatment study. Cognitive restructuring techniques were taught to 28 nonclinical high-worriers, 14 of whom served as a control group in a lagged waiting-list design. Results showed that the Penn State Worry Questionnaire-Past Week (PSWQ-PW) was highly reliable and substantially valid in the assessment of both (a) weekly status of worry and (b) treatment-related changes in worry: average Cronbach's alpha was 0.91; average convergent correlation with a past-week adaptation of the Worry Domains Questionnaire [Tallis, F., Eysenck, M. W. and Mathews, A. (1992). A questionnaire for the measurement of nonpathological worry. Personality and Individual Differences, 13, 161-168.] was 0.63 and pre-post improvement on PSWQ-PW showed a 0.71 correlation with the Questionnaire of Changes in Experiencing and Behavior [Zielke, M. and Kopf-Mehnert, C. (1978). Veränderungsfragebogen des Erlebens und Verhaltens. Weinheim, Germany: Beltz Test Gesellschaft.]. It is concluded that the PSWQ-PW is a useful instrument for monitoring pathological worry in experimental and applied settings
Congestion Games with Failures - CGFs
No full textWe introduce a new class of games---congestion games with failures (CGFs), which extends the class of congestion games to allow for facility failures. In a basic CGF (BCGF) agents share a common set of facilities (service providers), where each service provider (SP) may fail with some known probability. For reliability reasons, an agent may choose a subset of the SPs in order to try and perform his task. The cost of an agent for utilizing any SP is a function of the total number of agents using this SP. A main feature of this setting is that the cost for an agent for successful completion of his task is the minimum of the costs of his successful attempts. We show that although BCGFs do not admit a potential function, and thus are not isomorphic to classic congestion games, they always possess a pure-strategy Nash equilibrium. We also show that the SPs' congestion experienced in different Nash equilibria is (almost) unique. For the subclass of symmetric BCGFs we give a characterization of best and worst Nash equilibria. We extend the basic model by making task submission costly and define a model for taxed CGFs (TCGFs). We prove the existence of a pure-strategy Nash equilibrium for quasi-symmetric TCGFs, and present an efficient algorithm for constructing such Nash equilibrium in symmetric TCGFs
Penn-Jersey Urban Peregrine Partnership Kid's Book
No full textThis activity booklet was developed as part of the educational component of the Penn-Jersey Urban Peregrine Partnership. Its main purpose is to promote awareness and increase understanding of the pergrine falcom's struggle for survival. The games, activities, and coloring pages are designed for children ages 3-10.A cooperative project between the NJDEP Division of Fish, Game, and Wildlife's Endangered and Nongame Species Program and Pennsylvania Game Commission and Pennsylvania Wild Resource Conservation Fund, through a grant by the William Penn Foundation
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